Hi, If you want just a module developed I can do that or if you want an inventory with POS system here is an inventory system that you are looking for, ready, tested and fully functioning, very simple to use, however it can still be customized, bellow are its function;
Reference to Client Using it on freelancer: https://www.freelancer.com/projects/php/Software-for-retail-store/
>>Business information
>>Employee/ staff information
>>customer information
>>Inventory Management
>>Purchase Invoice Management
>>Local Purchase Order Management (LPO)
>>Point of sale integration (POS)
>>Sales profit and loss analysis between dates
>>User Access restrictions
>>Reports generation and flexible record search methods
>>Simple user interface and easy to learn
>>Can still be customized according to user preference
Its developed in vb.net and SQL Server
Inbox me for demo videos and overview documentation. thank you